Sunday, 7 December 2014

Cultural evolution: everyone is an expert

Popular blogger Jerry Coyne has persisted for many years in writing about cultural evolution - despite plainly not knowing anything about it. Here is a quote from his most recent effort:

Cultural evolution is simply the spread of beliefs or practices through assimilation. Such evolution differs from genetic evolution in two important ways. While genes spread only from parent to offspring (‘vertically”), cultural traits can also spread “horizontally”: in the case of religion, by imitation, conversion, or conquest—processes much faster than the spread of genes. Second, while genetic evolution depends on a single criterion of fitness—the number of offspring produced by the carrier of a gene—cultural traits spread by many different psychological and cultural mechanisms. The forces responsible for the spread of Marxism differ from those causing the success of Madonna.

Alas, almost every sentence is wrong. Cultural evolution also involves processes such as forgetting. It is not an "assimilation only" idea. There's horizontal gene transfer as well as horizontal meme transfer. Wikipedia has a large article on horizontal gene transfer. It is part of biology 101. Lastly, there's cultural fitness as well as organic fitness. Practically every definition of fitness that has been applied to the evolution of DNA genes has a direct counterpart in cultural evolution. Counting organic offspring can be replaced by counting cultural offspring - and so on.

Coyne's article was a review of a book by David Wilson. Here's Wilson on Coyne (from 2011):

In the second article, Wilson is fighting on home turf. Unlike Coyne, David Wilson does actually have a reasonable understanding of cultural evolution. It's a walkover for Wilson. IMHO, Coyne should learn something about this topic before discussing it in public any further.